This invention relates generally to the field of air handling, and more particularly to a mechanism for retaining panels in an air handler cabinet.
Many air handling units in the prior art are simply fabricated from sheet metal ducts that are brought together in the field to establish an enclosed flow path through which air is conducted. The sheet metal walls of the ducts readily conducts heat and provide little in the way of a thermal barrier so that energy flows into or out of the duct work. When the air handling unit is conducting conditioned air, this flow of energy into or out of the duct work is costly and places an unwanted load on the air conditioning equipment.
In addition, when the air handling unit is installed in an unconditioned space and is carrying cooled air, the outer casing of the unit xe2x80x9csweats.xe2x80x9d The moisture so developed runs off the unit onto the floor or equipment contained in the unconditioned space. This in turn leads to a safety hazard for people working in the area and causes damage to the equipment.
The traditional method for attaching AHU panels to each other is to use mechanical fasteners such as screws that are time consuming to remove and install, prone to getting lost and can strip out. Removal of the panels for equipment installation and maintenance is time consuming and does not allow complete access to the unit""s interior. Other similar panel retention designs place the retainer within the panel. If the retainer fails and requires replacement, the entire panel must then be replaced. Placing the retainer within the panel also places the retainer in the inner conditioned air stream, leading to external sweating or the use of expensive composite retainers to avoid sweating.
Briefly stated, an air handling unit (AHU) includes a frame structure and panels that are assembled to provide ducting for handling air. Each panel is rectangular with two sides and four edges. Each edge is integrally formed with the panel by extruding a perimeter of the panel. The extrusion has one flat edge that serves as a receiver for a cammed leg of a latch that is mounted in the same frame structure that retains the panel. While the latches are unengaged, the panel is inserted into the rectangular opening in the structure. The latches are then individually rotated 90 degrees such that the cammed leg pushes the panel further into the pocket, thus compressing a perimeter seal and eliminating air leakage.
By placing the panels in a freestanding frame and attaching them with quick release latches, the xe2x80x9cease of maintenancexe2x80x9d requirement is achieved. The inherent stiffness of foam filled panels also allows for the use of fewer retainers, further shortening the assembly/disassembly process. By placing the retainers in the frame and not the panel, the retainers do not cause a thermal path which leads to exterior sweating. Replacing defective or worn retainers is facilitated in that they are mounted in the easily accessible frame and not in the panel. In addition, the retainer preferably incorporates a cam shape that pushes the panel inward, compressing the perimeter seal as the latch is engaged.
According to an embodiment of the invention, an air handling unit includes a frame structure; at least one panel which fits into a corresponding opening in the frame structure formed by first, second, third, and fourth sides of the frame structure, wherein the first and third sides are substantially parallel and the second and fourth sides are substantially parallel; the panel having first, second, third, and fourth edges, wherein the first and third edges are substantially parallel and the second and fourth edges are substantially parallel; at least the first edge including a pocket formed therein; at least the first side including a latching mechanism therein; the latching mechanism including a rotatable cammed leg, such that when the leg is in a first position, the leg is within the first side, and when the leg is in a second position, the leg extends outside of the first side, such that when the panel is fitted into the frame structure such that the first edge of the panel is adjacent the first side of the frame structure, and the leg is in the second position, the first edge of the panel is latched to the first side of the frame structure.
According to an embodiment of the invention, an air handling unit includes a frame structure; at least one panel which fits into a corresponding opening in the frame structure formed by a plurality of sides of the frame structure; the panel having a plurality of edges corresponding to an equal number of the plurality of sides of the frame structure; at least one of the plurality of edges including a pocket formed therein; and means for latching the at least one of the plurality of sides to the at least one edge containing the pocket, the means for latching being contained within at least one of the plurality of sides of the frame structure.